Question

The magnitude of electric field E in the annular region of a charged cylindrical capacitor

• A. Is same throughout
• B. Is higher near the outer cylinder than near the inner cylinder
• C. Varies as $\frac{1}{r}$, where r is the distance from the axis
• D. Varies as $\frac{1}{r^2}$, where r is the distance from the axis

Answer 1

The correct option is C Varies as $\frac{1}{r}$, where r is the distance from the axis

The magnitude of electric field in the annular region of a charged cylindrical capacitor is given by $E=\frac{1}{2\pi {ϵ}_0}\frac{\lambda }{r}$ where $\lambda$ is the charge per unit length and r is the distance from the axis of the cylinder. Thus $E\infty \frac{1}{r}$